The CEX IO exchange is not a scam. Make sure you completely verify your account and two-factor the security of your login. Check out the platform and the people who built it. Read the full review.
So far the Official Dash Wallet is the best wallet I have experienced on mobile and would recommend it for everyone.
As for purchasing DASH, I use the Abra app.
It is definitely possible to convert your cryptoassets to precious metals efficiently and effectively. If you are in possession of Ethereum Classic simply trade it for BTC and you can use a platform such as Vaultoro to trade BTC for GOLD almost instantly.
If you want gold bullion, rare coins...